Thirst
by MayFairy
Summary: Doctor Who AU. The Doctor and Emma get stranded on a desert planet. Emma keeps taking off more clothing to avoid overheating, and the Doctor makes a point of definitely not noticing. Denial is a beautiful thing. 3rd in out-of-order ficlet series about Doctor!Regina and Companion!Emma.
**Set a few months after _Because It's Always Funny._**

 **(The title of this fic is why I should never be allowed to do anything ever)**

* * *

"So, do you want to explain to me one more time why your oh so incredible spaceship _literally ditched us in the middle of the desert_?!"

The Doctor grits her teeth and rolls her eyes at Emma's incredulity. It got old half an hour ago, but the blonde just isn't shutting up. "Hostile Action Dispersal System," she says, for the third time, "We were under attack, and it was serious. So the TARDIS relocated to protect itself."

"Leaving us stranded," Emma summarises, "On a desert planet."

"We're not stranded, we're just in for a long walk," the Doctor says, coming to a stop and turning around to put her hands on her hips and fix her with a glare, "One that is going to be much longer if you don't stop complaining. I am not above gagging you if necessary."

Emma's eyebrows shoot up, and she grins mischievously. "Oh yeah? Well, for the record, Doctor, my safe word is Tallahassee."

With that, she brushes by the Doctor and saunters onward down the sandy hill, leaving the Time Lady with a short circuit in her brain and the taste of bewilderment in her mouth.

 _Did she just -_

Sex isn't something the Doctor tends to give much thought. Usually. And sometimes that kind of thing goes right over her head, but she's pretty sure _that_ innuendo was unmistakable.

Swallowing hard, she shakes herself of the mental block and hurries to catch up (without _looking_ like she's hurrying, of course). While doing so, she deliberately _does not_ notice how being behind Emma gives her a perfect view of her perfect ass in the jeans that the Doctor has taken great joy in criticising in the past but is now rather appreciative of.

Or, you know, would be, if she were noticing that sort of thing, which she isn't.

"So when you say a long walk, just how long are we talking?" Emma asks as the Doctor finally catches up to her, putting said jeans out of sight and mostly out of mind.

The Doctor is glad for the chance to dig in her blazer pocket and busy herself by checking the sonic for the exact distance. "49.7 miles, apparently."

"What the shit?!" Emma cries. "Doc, that's _ages_! It'll take hours."

"Yes, it will, so I suggest you don't get on my nerves before we've barely started," the Doctor snaps, "Call me Doc one more time and I'll-"

Emma crosses her arms, eyebrow up. "You'll what, exactly?" When the Doctor can give no immediate answer, the grin from before returns. "Spank me? Teach me a lesson?"

The Doctor feels her face get impossibly hot and she stares at her companion with indignant fury. "I'll - think of _something_!" She seethes, before storming ahead.

She walks for a good few minutes before Emma is back at her shoulder.

"Look, Doctor, I'm sorry," the human says, taking deliberate care with the title, in a way that only makes the strange heat in the Time Lady's chest (which has nothing to do with the three suns) worse. "Being a pain in the ass is kind of my prerogative."

"You don't say," the Doctor replies coolly.

"How long will this walk take?"

"About half a day, assuming that you'll need to stop and rest a few times."

Emma groaned. "Well, at least I have good company. Not sure I can say the same for you, though."

A small laugh escapes the Doctor's throat before she can stop it. Staying mad at Emma, it seems, is impossible, no matter how easily the blonde is able to get under her skin. Emma grins and they continue to walk in comfortable silence.

* * *

The silence lasts all of half an hour, and the Doctor has to wonder just how much self-control Emma had been exhibiting to keep quiet that long.

"Okay, we've got to think of a way to pass the time," the human blurts.

"I've always found that to be a ridiculous phrase," the Doctor says with a thoughtful frown, " _Pass the time._ You can't, time just passes, it's not affected by what any being chooses to do with it. And yet, various phrases around such an idea exist in more cultures than I can name. Honestly, the ideas you non time-sensitives get."

"But sometimes it goes fast, and sometimes it seems to drag on forever," Emma points out.

The Doctor snorts. "Maybe for you. And that has everything to do with cognition, dear, and nothing to do with time."

"Oh, I guess that's true," Emma says, making a face. "Fuck it's hot." She slips out of her jacket and ties it around her waist, leaving her in her white wifebeater, which is already starting to stick to her skin in a few spots.

Not that the Doctor is looking, of course.

"How are you not dying in that blazer? It's navy," Emma asks, frowning at her.

"Time Lord physiology, I can quite easily withstand greater extremes than you."

"But you have that lower body temperature, so shouldn't that make you _more_ susceptible to heat than me?"

"Don't try and apply human logic to a Time Lord body," the Doctor says curtly.

Emma rolls her eyes and they continue on without speaking for another ten minutes. The silence is this time broken by Emma letting out a groan of frustration. It isn't until a pocket knife comes out of her pocket, however, that the Doctor is concerned.

"Miss Swan, just _what_ do you think you're doing?" She asks sharply, crossing her arms.

"Emma."

"Just answer the question, Em-ma," the Doctor says with great impatience, tapping her fingers against her arm.

"Reducing the risk of my dying of heatstroke in the next eleven and a half hours."

Emma gets the tiny pair of scissors out and starts cutting the fabric of her jeans around the middle of her thigh. It's all the Doctor can do not to gape - she's not sure how she feels about the destruction of clothing, no matter how many snide comments she's made over the last three months about these particular jeans.

It takes a minute or two, but finally the large pieces of denim fall onto the sand and Emma is left in some makeshift cutoff shorts and her converse.

She has nice legs, the Doctor thinks. Speaking objectively of course, because Emma is human and the Doctor _does not_ notice things like that. Besides, they're not as nice as her arms.

"Okay, I'm good," Emma says, letting out a sigh of relief.

"If you're done decimating your wardrobe, can we get going again?" The Doctor asks irritably. "Also, I hope you realise that I will tolerate zero complaining when your now very exposed limbs get sunburnt."

"I can handle sunburn."

"If you say so."

* * *

"Okay, I've got to ask."

The Doctor braces herself for what no doubt will be another ridiculously stupid question, and turns to look at Emma. "What?"

"Why question marks?" Emma nods to the decorations on each end of her shirt collar.

The Time Lady opens her mouth to answer, only to come up short. "You know, I have absolutely no idea," she admits, with surprise. The expression on her face must be quite comical because Emma starts laughing heartily, and the Doctor starts laughing too.

There's something so natural about laughing with Emma the way she's been doing more recently. Before Emma, she can't remember ever laughing quite like this, throughout her whole long life. Not even with Daniel.

When the laughter finally fades, they're just grinning at each other breathlessly as they walk, and the Doctor notices how bright Emma's green eyes are in the mirth's wake and how they light up the rest of her face in a way the sunlight can't.

But then there's white fabric in the way and the Doctor is blinking in confusion until she realises Emma is peeling her shirt off. The sweat soaked fabric clings to her body as she tries to pull it over her head, and the Doctor ends up staring again as a toned stomach is revealed to her.

"Checking out my abs, Doctor?" Emma asks with a grin, making the Doctor snap out of it and roll her eyes at the blonde, who is tucking the white fabric half into her jeans pocket so that it hangs out in a way that looks ridiculous.

"Don't flatter yourself, dear," the Doctor tells her, sniffing and pointedly looking away from where Emma is now only wearing a red sports bra and her cutoff shorts. "I'm simply thinking about how you seem to be set on making sure almost your entire body is sunburnt by the time we get off the planet, and the amount of whining I'm going to have to endure as a result of it."

"Your concern is touching," Emma says dryly.

"Well, you humans are delicate, I have to at least _try_ and look after you when you're in my care."

"I'm in your _care_ now?"

"You have been since the moment you stepped into my ship, Emma, it's just how these things work. I show you time and space, and I do my best to keep you _safe_ from time and space."

"And if I'm really stupid and get hurt despite your best efforts?" That brings up a rather unwelcome thought of a truly injured Emma, which makes the Doctor's stomach turn, and she has to remind herself that they're talking about _sunburn_.

"Well, then I expect no complaints or requests to help you put aloe vera all over yourself," the Doctor tells her.

Emma grins. "Damn. Not even with bribery?"

That makes the brunette snort. "And just what, pray tell, could you bribe me with to make me do such a thing?"

Emma leans in, until their faces are only an inch apart even though they're not quite facing one another, and the Doctor feels her respiratory bypass kick in as she briefly forgets to breathe. "Whatever. You. Want," the blonde half-whispers, making the Doctor lick her lips nervously.

Then Emma is gone from her personal space and striding on ahead as if nothing has happened, leaving the alien standing frozen until she shakes some sense back into herself.

"In all seriousness," her companion calls back to her, turning around to walk backwards so she can grin at her, "I was thinking maybe I could promise not to speak for an entire day. A whole day's silence. How does that sound?"

"Make it two and you've got a deal," the Doctor calls back, internally scolding her hearts for getting so out of sync and willing them to fall back into regularity a bit faster since there is absolutely _no reason at all_ for them to be acting out in this way.

 _Denial_ , she thinks as she adds power to her stride to catch up, _is a beautiful thing._

* * *

 **Thanks to Mrs. 11th for this prompt, it was SO MUCH FUN to write and such a great little idea. I'll consider any prompts given to me for these two so send them in if you've got any!**

 **Thanks for reading, let me know what you thought!**


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